Cycling shoe with slow-rebound nanofoam

ABSTRACT

A cycling shoe including an upper part configured to receive a foot of a user, an outsole disposed on a bottom of the cycling shoe, and a midsole disposed between the upper part and the outsole, the midsole including a nanofoam and having a hardness between 45 D and 65 D, inclusive, as measured by a durometer.

RELATED APPLICATION DATA

This application claims priority to U.S. Provisional Application No. 63/122,767, filed Dec. 8, 2020, the disclosure of which is hereby incorporated by reference.

BACKGROUND

Traditional midsoles are usually constructed from EVA (ethylene vinyl acetate) foam, which is a combination of two types of plastic. EVA rebounds much like a ball—when compressed, the stored energy wants to return, or spring back. Midsoles can also be constructed from polyurethane, which is another type of material that behaves like plastic or rubber. However, polyurethane is not as commonly used as EVA because it tends to be heavier and firmer.

The use of EVA in flat pedal shoes can cause problems when the user is mountain biking and the user rides over rough terrain. In particular, EVA midsoles will compress and decompress quickly, resulting in the rider's foot bouncing off the pedals, leading to a loss of stability and control. Accordingly, improvements are needed in midsole technology.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a novel shoe and various components of the shoe according to an exemplary embodiment.

FIG. 2 illustrates a diagram of a indenter of a D scale durometer (i.e., Shore D test standard).

FIG. 3 illustrates an example of the nanofoam/mute foam according to an exemplary embodiment.

FIG. 4 illustrates a flat pedal shoe incorporating the novel nanofoam midsole according to an exemplary embodiment.

FIG. 5 illustrates additional variations of flat pedal shoes incorporating the novel nanofoam midsoles according to an exemplary embodiment.

FIGS. 6A-6D illustrate a nanofoam midsole having a novel geometry according to an exemplary embodiment.

FIGS. 7A-7C illustrate another nanofoam midsole having a novel geometry according to an exemplary embodiment.

DETAILED DESCRIPTION

The inventors have discovered a novel midsole material and novel construction method for a flat pedal cycling shoe that solves the above-mentioned problems. In particular, the inventors have constructed a novel midsole comprised of a slow-rebound foam, rather than a fast rebound foam and a novel cycling shoe incorporating the novel midsole. The use of slow-rebound foam improves stability and control on flat pedal cycling shoes.

FIG. 1 illustrates a novel shoe 100 and various components of the shoe according to an exemplary embodiment. The upper part of the shoe is the part of the shoe that is configured to receive and enclose a user's foot. The upper shoe holds the foot in place and prevents excessive movement of the foot within the show. The outsole is disposed on the bottom of the shoe and is the part that contacts the ground. Since the outsole contacts the ground, the outsole provides traction and determines how the shoe moves over different types of terrain. The outsole also affects the rigidity and flexibility of the overall shoe. Not shown is the insole, which sits within the shoe in the upper part, is disposed above the midsole, and contacts the bottom of the foot of the user.

As shown in FIG. 1, the midsole is disposed between the upper part of the shoe and the outsole. The midsole is typically where cushioning technologies and features designed to control pronation are located and greatly influences the quality, durability, and longevity of the show.

Shoe 100 includes a novel midsole constructed of slow-rebound nanofoam. The novel midsole can be created from a moldable nanofoam that can be injection molded into the desired shape. In this case the midsole can be constructed entirely, or nearly entirely, from the nanofoam. Nanofoams are nanostructured porous materials. The nanofoam can have, for example, pores with diameters less than 100 nanometers. By molding the nanofoam, the entire midsole can be made from this material. Another technique for creating the novel midsole is to use a sheet of nanofoam material and insert it into the midsole. In this case, the midsole comprises a die cut sheet of nanofoam. However, this technique is not as effective as molding, which allows the nanofoam to conform to the exact size and shape required for a particular midsole.

Nanofoam has slow rebound that absorbs energy and compression, resulting in the rider's feet remaining connected to the pedals. A side effect of this slow rebound foam is that the pedal pins, which are metal, remain engaged into the outsole more securely, as the slow foam does not rebound quickly and result in a disengagement of a pedal pin. The nanofoam also provides chatter reduction—a damping effect that reduces the effect of vibrations on the cyclist's foot.

Nanofoam can be constructed and/or molded in different densities and hardness levels. If the nanofoam is constructed or molded to have a low hardness, then the energy absorption of the nanofoam midsole is reduced. Additionally, the hardness affects density and malleability, and very low hardness nanofoam midsoles can result in a midsole that is too malleable, resulting in a midsole that rebounds too slowly. Conversely, a nanofoam midsole with a very high hardness value will not provide enough malleability and damping. In this case, the nanofoam midsole may rebound too quickly and the hardness of the midsole can result in chatter (i.e., vibrations from the pedal, bicycle, and/or road) reaching the feet of the user rather than providing the desired damping effect.

Additionally, another factor that must considered in determining an optimal hardness for the nanofoam midsole is the temperature sensitivity of the nanofoam and the resulting changes in malleability and energy absorption caused by temperature fluctuation. For example, a nanofoam midsole having a first hardness value that performs reasonably well at room temperature can become too malleable when exposed to higher temperatures (such as temperatures simulating the temperature when in use by an athlete or cycler). Alternatively, a low temperature may result in the midsole becoming too hard and/or rigid, thereby reducing the benefits of the slow rebound nanofoam.

The inventors have determined an optimal hardness of the nanofoam that optimizes the performance of the nanofoam midsole specifically in the context of a cycling shoe. Specifically, the inventors have determined that a nanofoam midsole having a hardness value, as measured by a durometer, of between 45 D-65 D, inclusive. In other words, the nanofoam midsole has a hardness value of between 45-65, inclusive, on the D scale of the Durometer. As is appreciated by one of skill in the art, a durometer or shore durometer is a standardized way to measure the hardness of materials like rubber (elastomers) and plastics and the D scale is typically utilized in the field to measure hardness of hard rubbers, plastics, and thermo plastics.

The different scales of the Durometer utilize different “indenters” which are used to measure the resistance of the material being tested to being indented. A diagram of the indenter of the D scale durometer (i.e., Shore D test standard) is shown in FIG. 2. For the D scale, an indenter 200 having a sharp tip that ends with a 30 degree cone angle 201 (i.e., the angle between opposite walls of the cone as measured from the tip) is applied with 10 pounds of spring force to the material being tested 203 to determine hardness. The tip 202 of the D scale indenter has a rounded end that is 0.1 mm in diameter.

According to an exemplary embodiment, the nanofoam midsole has a hardness value as measured by a durometer of between 50 D-60 D, inclusive (i.e., on the D scale of the durometer, a Shore D test standard). The inventors have determined that a nanofoam midsole having a hardness value in this range provides an optimal characteristics for malleability, force absorption, rebound speed, damping, and temperature tolerance when used in a cycling shoe and in the context of cycling. According to a further exemplary embodiment, the nanofoam midsole has a hardness value as measured by a durometer of 55 D or within 1 unit of 55 D (i.e., between 54 D-56 D, inclusive).

FIG. 3 illustrates an example of the nanofoam/mute foam according to an exemplary embodiment. The nanofoam can be injection molded into the required shapes to construct the midsole. This is slow rebound and closed-cell nanofoam that performs like a suspension system to keep feet on the pedals. The foam conforms to pins for greater power transfer.

FIG. 4 illustrates a flat pedal shoe incorporating the novel nanofoam midsoles disclosed herein. The shoe can have a microfiber fast drying upper part, a rubber outsole, a nanofoam molded midsole, and 3d injection molded EVA insoles. FIG. 5 illustrates additional variations of flat pedal shoes incorporating the novel nanofoam midsoles.

The geometry of the novel nanofoam midsole can also impart additional benefits. In particular, the nanofoam midsole can be constructed with a geometry that increases rigidity, thereby enabling the use of less hard nanofoam midsoles that have slower rebound characteristics while maintaining a minimal level of rigidity.

FIGS. 6A-6D illustrate a nanofoam midsole 600 having a novel geometry according to an exemplary embodiment. As shown in FIGS. 6A-6D, this nanofoam midsole 600 has a honeycombed structure that begins approximately 15-25% below the front of the nanofoam midsole (with the front being at the front of the shoe near the users toes) and that extends to the rear of the nanofoam midsole (i.e., at the heel). Each hexagonal cell of the honeycombed midsole 600, such as cell 601 in FIG. 6A, can be further split into 3 pentagonal shapes, as shown in the figures. Additionally, as shown in FIGS. 6A-6D, the midsole 600 has a raised perimeter/edge that extends to a greater height than the rest of the midsole and imparts additional rigidity.

FIGS. 7A-7C illustrate another nanofoam midsole 700 having a novel geometry according to an exemplary embodiment. As shown in FIGS. 7A-7C, this nanofoam midsole 700 has a series of grooves, such as groove 701 in FIG. 7A, which run along the midsole in a front-rear direction, begin approximately 15-25% below the front of the nanofoam midsole (with the front being at the front of the shoe near the users toes) and end at approximately the midway point between the front and rear of the midsole. As shown in FIG. 7A, the midsole 700 can have six grooves. Additionally, as shown in FIGS. 7A-7C, the midsole 700 has a raised perimeter/edge that extends to a greater height than the rest of the midsole and imparts additional rigidity.

Having described and illustrated the principles of our invention with reference to the described embodiment, it will be recognized that the described embodiment can be modified in arrangement and detail without departing from such principles.

It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this disclosure is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present disclosure. 

1. A cycling shoe comprising: an upper part configured to receive a foot of a user; an outsole disposed on a bottom of the cycling shoe; and a midsole disposed between the upper part and the outsole, the midsole comprising a nanofoam and having a hardness between 45 D and 65 D, inclusive, as measured by a durometer.
 2. The cycling shoe of claim 1, wherein the upper shoe comprises an insole disposed above the midsole.
 3. The cycling shoe of claim 2, wherein the insole comprises an ethylene vinyl acetate (EVA) foam.
 4. The cycling shoe of claim 3, wherein the insole is constructed by injection molding the EVA foam.
 5. The cycling shoe of claim 1, wherein the midsole is constructed by injection molding the nanofoam.
 6. The cycling shoe of claim 1, wherein midsole comprises a die cut sheet of nanofoam.
 7. The cycling shoe of claim 1, wherein the nanofoam comprises pores having a diameter of less than 100 nanometers.
 8. The cycling shoe of claim 1, wherein the midsole has a hardness between 50 D and 60 D, inclusive, as measured by a durometer.
 9. The cycling shoe of claim 8, wherein the midsole has a hardness between 54 D and 56 D, inclusive, as measured by a durometer.
 10. The cycling shoe of claim 9, wherein the midsole has a hardness of 55 D as measured by a durometer.
 11. The cycling shoe of claim 1, wherein the upper part comprises a microfiber material.
 12. The cycling shoe of claim 1, wherein the outsole comprises a rubber material.
 13. The cycling shoe of claim 1, wherein the midsole comprises a honeycombed nanofoam structure.
 14. The cycling shoe of claim 1, wherein the midsole comprises a grooved nanofoam structure.
 15. The cycling shoe of claim 1, wherein the midsole comprises a raised perimeter.
 16. A cycling shoe comprising: an upper part configured to receive a foot of a user; an outsole disposed on a bottom of the cycling shoe; and a midsole disposed between the upper part and the outsole, the midsole comprising a nanofoam and having a hardness between 55 D and 60 D, inclusive, as measured by a durometer.
 17. A cycling shoe comprising: an upper part configured to receive a foot of a user; an outsole disposed on a bottom of the cycling shoe; and a midsole disposed between the upper part and the outsole, the midsole comprising a nanofoam and having a hardness between 55 D and 60 D, inclusive, as measured by a durometer, wherein the midsole comprises a raised perimeter. 